6-Styryl-5-(het)arylfurazano[3,4-b]pyrazines have been obtained by novel C-H functionalization, which is a particular case of the nucleophilic substitution of hydrogen (S-N(H)). The process is initiated by the Michael addition of morpholine at the C=C double bond of beta-nitrostyrenes, and the subsequent addition of the generated carbanion to C-6 of 5-(het)arylfurazano[3,4-b]pyrazines, followed by elimination of nitrous acid and morpholine. It has been shown that in this case, only beta-nitrostyrenes bearing electron-rich substituents on the aromatic ring are involved in arylalkenylation of furazano[3,4-b]pyrazines